Lug Analysis under transverse loading

[fl11]

Hi,

I have found out, in this thread thread2-210058, that there was another ESDU, 06021, about strength of lugs under transverse load.

I found out recently that there could be a huge difference of the allowable transverse force wether you are using Bruhn/Niu Graphs(multiple curves for different material) or ESDU 91008 graphs (one curve for all Aluminum and one curve for all Steel.)

My company is still in the process of getting back its membership to ESDU, so I wasn't able to get my hand on ESDU 06021 for now, but I was wondering if anyone of you had. Would it be possible (legal?) for any of you to discuss their conclusions? Do they get new curves to get Ktru somewhere between ESDU 91008 and Bruhn/Niu or closer to one or the other?

Or do you know if they published some article on that subject somewhere?

Thank you very much for your inputs.

 

[mohr]

Hi francoilanbert11 .

A good source on Lugs is the Bell structural Design manual.
It is very detailed source of practical design.

Cheers !

 

[fl11]

Thanks for the information. I will try to find this book if I can. But as far as I know, most of the analysis of lugs are based on Cozzone article and Hobblit and Melcon article. (Is it the case for the manual you suggested?) The main problem, for transverse loading, is that they suggest to use some curves that comes from "Crude theory" as they said andthose curves are different for different Aluminum Alloy. Those curve are probably very conservative.

ESDU 91008, on the other hand, suggest to take only one curve for Aluminum alloy and one curve for Steel alloy. The results from those two curves can be huge and can make a difference between a negative margin of safety and a positive one. ESDU 06021 seems to have derived some new curves based mostly on FEM which take into account the difference in the material properties. So I was guessing those curves could replace those of Hobblit and Melcon that we find in Bruhn and Niu. But won't know until I can see those curves and all the theory behind them. That is why I wanted to know here if any of you had been in contact with this new ESDU.

 

[inertia4u]

See if this helps...

-----
Nert

 

[taoofeng]

Here is the method as given in the Air Force Stress manual. It is where the Lockheed method came from. (The subscripts tend to be rather tiny so hopefully you can read it).

 

[edbgtr]

Hi Francois

See also thread31-226131 and the reference to the NTIS stress manual. The lug analysis section appears to be very good.

Ed.